1. Field of the Invention
The present invention relates to the general art of hydraulic and earth engineering, and to the particular field of foundation underpinning. Most particularly, the invention relates to correcting settlement of a static structure, such as a building or element of a building.
2. Description of the Prior Art
As described in U.S. Pat. No. 5,246,311 (West, et al.), the disclosure of which is fully incorporated herein by reference, settling of static structures, such as buildings, is a common phenomenon and can have serious consequences, including damaging or weakening load bearing elements.
As also discussed in the West, et al. patent, the art contains disclosures of various solutions to the aforementioned settling problem. These solutions often include underpinning the structure by driving piers into the ground adjacent to the structure and attaching the structure to those piers after the structure has been elevated to a desired position. For example, one method includes drilling pier holes near strategic sites around the perimeter of a building structure to be repaired and placing piers of concrete to extend from the foundation of the building structure to bedrock and then fixing those placed piers to the building to support the building. While often difficult, heretofore, this was sometimes the only practical method of correcting a settling problem for a structure.
The West, et al. patent discloses a method for correcting the settling problem. The West, et al. patent discloses a system that comprises a plurality of elements each of which performs one of the functions required to correct the building settling problem.
The West, et al. system includes a pier-driving unit that is attached to the structure to be lifted and uses that structure as the base to drive a pier to a point of refusal. The West, et al. system further includes a bracket which is fixed to the building and a secondary system that is attached to the structure-affixed bracket after the pier has been driven to the point of refusal.
The West, et al. secondary system is actuated after the pier-driving unit is removed and, using the pier as a base, lifts the foundation or building to a desired position. The building-affixed bracket is then attached to the pier and the secondary system is removed.
As used herein, the term xe2x80x9cpoint of refusalxe2x80x9d means the lowest location beneath the surface of the supporting body, such as the ground, to which an element can be driven using a static structure on the supporting body (ground) as its base against which an element-driving force is exerted. For example, using a building as a base against which pier-driving force is exerted, a pier is driven into the ground supporting the building until the building""s weight can no longer provide sufficient support for forcing the pier further into the ground. At that point, further pressure on the pier will no longer drive the pier further into the ground, but, instead, will lift the building. This is the point of refusal.
While the system disclosed in the West, et al patent works well, it can be improved by making that system easier and more efficient to manufacture, set up and use.
Furthermore, there are some situations where the bracket of the West, et al. system cannot be easily used. For example, in some situations, there is not room adjacent to the foundation to provide sufficient clearance for the foundation-supporting elements of the West, et al. system to be placed beneath the foundation. Thus, the foundation cannot be efficiently supported so the pier cannot be efficiently driven into the ground and the foundation efficiently lifted using the system disclosed in the referenced patent. The West, et al. system is not versatile enough to be most efficiently used in such a situation.
Thus, the system disclosed in the referenced West, et al. patent can be improved by making it more versatile. Still further, there are some situations when a foundation has simply dropped away from a building, and the entire building need not be moved, only the foundation needs to be lifted back into position subadjacent to the building. These situations may be fairly simple to remedy. However, the numerous parts of the referenced West, et al. system may somewhat vitiate the ease of correction, especially from a cost-effective basis.
Therefore, the system disclosed in the referenced West, et al. patent can be improved by improving the simplicity thereof and providing a system that is cost-effective in simple operations.
These, and other objects are achieved by a static structure jacking or lifting system that includes a one-piece, monolithic bracket that is expeditiously attached to the structure to be lifted and to a simple system which is used to drive a pier through a sleeve on the bracket and into the ground beneath the structure to be lifted. The same bracket is used to support the structure during and after raising of the structure to a desired position. The bracket is simply placed beneath the structure to be lifted and is held in place by friction. An alternative bracket is also simple to attach to the structure and is easily attached to the system for raising the structure. The alternative bracket is used in situations where access. subadjacent to the structure is limited or prevented. The alternative bracket is fixed to the structure by attaching means, such as bolts, for attaching the structure to the bracket. However, with the exception of the bracket, which is a simple, one-piece, monolithic element in both cases, the overall system is the same for both situations
The one-piece, monolithic configuration of the bracket simplifies the system and makes manufacture thereof efficient while making set up and use more efficient than the system disclosed in the referenced patent. The use of friction or attaching means to fix the bracket to the foundation makes the system embodying the present invention quite versatile as compared to other systems. The simplicity and minimum number of elements of the present system makes it more amenable to simple jobs than prior systems.
The principal objects and advantages of the present invention include: providing a structure jacking system and method; providing such a system and method which are efficient to set up and use; providing such a system and method which are adaptable to various field conditions; providing such a system and method which securely grip a foundation wall for raising same; providing such a system and method which provide long-term foundation stability; providing such a system and method which can be used with relatively little training; providing such a system and method which are versatile in application to various foundation conditions; and providing such a system and method which utilize relatively common and easily-fabricated equipment, components and assemblies for installation.